Wrist fractures and hip fractures are perhaps some of the most common skeletal site injuries of humans. For example, wrist fractures have an incidence of about 1 in 500 for the general population and hip fractures, particularly amongst elderly Americans, are common. As a further indicia of the commonality of hip fractures amongst older Americans, in the year 2000 more than 340,000 older Americans sustained hip fractures at a cost of nearly $20 billion. More than 90% of such hip fractures are associated with falls. These few statistics alone demonstrate the need for protective and preventive technology to avoid such fractures rather than have our country and its economy sustain the economics of post injury treatment.
Devices used as external protectors are of course known and have been used in the past for almost every sensitive area of the body from head to shoulder, to forearm, to wrist, to knee, to shin, to ankle, etc. Just to name a few examples of such devices: air bags, crash helmets, foam rubber dash boards, playground surfaces, track and field pits, athletic footwear with cushions, etc. To date, none of these devices as used have succeeded in developing a structure that equals the impact resistance ability of normal human bone. Put another way, the human skeleton is already optimized by nature to absorb impact. This is because of the physics involved. The skeleton seems to recognize almost a fact of physics, i.e., that if collision time is extended or increased the forces of impact will decrease. This implies that if there is some deformation of the impact surface before zero velocity is reached, the forces experienced will decrease. As a result, for example, we now have soft nosed cars, rather than the hard thick steel front ends of past days, for example, the 1930's and 1940's. However, this recognition that slow deformation decreases the forces of impact is one thing, putting this to use in making body part protectors, i.e., pads, is quite another thing.
The current design of energy absorbing orthotic devices uses a variety of foamed and/or microcellular thermoplastic materials known in the industry as thermoplastics (TP's) or thermoplastic electomers (TPE's), gels, etc. In orthopedic technology, these materials have been applied to the foot for use in orthotic and athletic footwear. However, no one has yet made a material paralleling the internal lattice-like structure called trabeculation with cells and fluids interspersed among the trabecula that occurs in human bone. The property of human bone referred to here is “viscoelastic properties”. By viscoelastic we mean to define a material which has some of the properties of a solid, and some noncompressable properties of a fluid that demonstrates both viscous and elastic behavior under stress, which results in a continuous creep or displacement as force increases, resulting in an even greater resistance to motion.
Accordingly, it is a primary objective of the present invention to provide new orthotic devices and methods which employ viscoelastic polymeric materials in pads to provide a response to impact forces that mimics the trabeculator architecture response of human bone and the cells and fluid interspersed within the lattice-like structure of human bone. The orthotic devices for which the impact pad containing the viscoelastic polymer may be used are many and not intended to be limiting. Those include heel cushions, hip pads, bone spur pads, wrist pads, elbow pads, shoulder pads, thigh pads, forearm pads, head protectors and shin and ankle protectors, among others.
The method and manner of accomplishing the primary objective as well as others will become apparent from the detailed description of the invention which follows.
It is understood that minor changes and modifications that occur to one of skill in the art may be made and still fall within the scope and spirit of the invention.